<template>
  <scroll
    class="index-list"
    :probe-type="3"
    ref="scrollRef"
    @scroll="onScroll"
  >
    <ul ref="groupRef">
      <li
        v-for="group in data"
        :key="group.title"
        class="group"
      >
        <h2 class="title">{{group.title}}</h2>
        <ul>
          <li
            v-for="item in group.list"
            :key="item.id"
            class="item"
            @click="onItemClick(item)"
          >
            <img class="avatar" v-lazy="item.pic">
            <span class="name">{{item.name}}</span>
          </li>
        </ul>
      </li>
    </ul>
    <div
      class="fixed"
      v-show="fixedTitle != ''"
      :style="fiexdStyle"
    >
      <div class="fixed-title">{{fixedTitle}}</div>
    </div>
    <div
      class="shortcut"
      @touchstart.stop.prevent = "onShortcutTouchStart"
      @touchmove.stop.prevent = "onShortcutTouchMove"
      @touchend.stop.prevent
    >
      <ul>
        <li
          v-for="(item, index) in shortcutList"
          :key="item"
          :data-index="index"
          class="item"
          :class="{'current':currentIndex===index}">
          {{item}}
        </li>
      </ul>
    </div>
  </scroll>
</template>

<script>
import Scroll from '@/components/scroll/scroll'
import useFiexd from './use-fixed'
// 计算属性
import useShortcut from './use-shortcut'
export default {
    components: { Scroll },
    // 下面使用了 emit 所以在vue3 中一般也会写一个emits  定义好有哪些自定义事件
    emits: ['select'],
    props: {
        data: {
            type: Array,
            default() {
                return []
            }
        }
    },
    setup(props, { emit }) {
        function onItemClick (item) {
          emit('select', item)
        }
        const { groupRef, onScroll, fixedTitle, fiexdStyle, currentIndex } = useFiexd(props)
        const { shortcutList, onShortcutTouchStart, scrollRef, onShortcutTouchMove } = useShortcut(props, groupRef)
        return {
            groupRef,
            onScroll,
            fixedTitle,
            fiexdStyle,
            shortcutList,
            currentIndex,
            scrollRef,
            onShortcutTouchStart,
            onShortcutTouchMove,
            onItemClick
        }
    }
}
</script>

<style lang="scss" scoped>
  .index-list {
    position: relative;
    width: 100%;
    height: 100%;
    overflow: hidden;
    background: $color-background;
    .group {
      padding-bottom: 30px;
      .title {
        height: 30px;
        line-height: 30px;
        padding-left: 20px;
        font-size: $font-size-small-s;
        color: $color-text-l;
        background: $color-heighlight-background;
      }
      .item {
        display: flex;
        align-items: center;
        padding: 20px 0 0 30px;
        .avatar {
          width: 50px;
          height: 50px;
          border-radius: 50%;
        }
        .name {
          margin-left: 20px;
          color: $color-text-l;
          font-size: $font-size-small-medium;
        }
      }
    }
    .fixed {
      position: absolute;
      top: 0;
      left: 0;
      width: 100%;
      .fixed-title {
        height: 30px;
        line-height: 30px;
        padding-left: 20px;
        font-size: $font-size-small-s;
        color: $color-text-l;
        background: $color-heighlight-background;
      }
    }
    .shortcut {
      position: absolute;
      right: 7px;
      top: 50%;
      transform: translateY(-50%);
      width: 20px;
      padding: 20px 0;
      border-radius: 10px;
      text-align: center;
      background: $color-background-d;
      font-family: Helvetica;
      .item {
        padding: 3px;
        line-height: 1;
        color: $color-text-l;
        font-size: $font-size-small-s;
        &.current {
          color: $color-theme
        }
      }
    }
  }
</style>
